Owing to the snow, Lucille is two days late and her start is bumpy when she falls ill. Lucille is called out from her sick bed to assist Trixie with a breech birth. Nadine Mulvaney (Tamla Kari), a single mother and exotic dancer in Soho, plans to give the baby up for adoption. But, Trixie is concerned that Nadine’s Rhesus Negative blood type might cause problems for baby.

Meanwhile, Nurse Crane (Linda Bassett) and Dr Turner (Stephen McGann) are caring for Ruth Gelin (Julie Legrand), an elderly Jewish woman suffering from bowel cancer. Ruth and her husband Arnold (Allan Corduner) are facing eviction from their home of several decades. The council have started to demolish their street as part of the slum clearance.

Charlotte: When Barbara arrived at Nonnatus House she wouldn’t say boo to a goose, and now she’s brave. We saw her get her confidence when she was in South Africa with Trixie. I think her relationship with Tom has really propelled her into adulthood and being a wife now. She’s looking after somebody who isn’t someone’s baby, and now she has to do his washing and also her own work. She’s definitely growing up.

Linda: Heidi has written a wonderful character that I can really play with. Nurse Crane is old fashioned, stern and rigorous, she’s not modern, lax or free and easy, the way people can be nowadays. She is quite fixed but has a fun side which I recognised in the adults I knew when I was growing up. Every now and again I get a chance to express her playful side. She is also a very good midwife, very kind to all the mothers in her care and has a great affection for the babies.

When Nurse Crane first arrived, Barbara and her shared a room, which would immediately make you feel sorry for Barbara - she had this woman going, "I’ve put a line down the centre of the dressing table so we have a side each" and that sort of thing. However, they became really close and my character was bridesmaid when she got married, so we’ve seen her fly the nest.

The new policeman, Sergeant Woolf, seems to be a thorn in Nurse Crane’s flesh. He is always there... like a one-man health and safety brigade... and he’s even more pompous than she is, so he is a bit of a match for her. Naturally, if you see your own bad qualities reflected in someone else, you don’t like them much do you?

Helen: Trixie and Christopher are still going strong; she’s really trying to be what she imagines he would want in a partner, by cooking meals for him. It’s quite interesting as he puts a little pressure on her to spend her first night with him, which really brings up thoughts on sex before marriage and the idea of contraception. She confides in him quite a lot about her drinking and he’s there for her as support outside of Nonnatus House. The only problem with their relationship is that he has an ex-wife, with whom he shares a child, who isn’t necessarily happy that Christopher is seeing a new women. His daughter Alexandra is lovely little girl who Trixie really takes to and they have quite a strong bond.

At the start of the series, Trixie is still sober and going strong with her AA meetings. We take a glimpse into one of her meetings, and it’s good to revisit that so we see that Trixie has this ongoing struggle with alcohol and it’s not fixed, it’s not solved. And you really hear her share and you hear how much time Trixie actually spends on this, how much time she spends going to AA meetings, but more importantly how much she thinks about drinking, or rather not drinking. Drink’s always on her mind and you really get to grips with her struggle and how at the forefront of her thoughts it still is, even though you see her not drinking, it’s still there.

Jennifer: Valerie is such an interesting character because she's really two ends of a spectrum - she’s incredibly warm and loving and makes very deep emotional connections with people but she's also got quite a fiery nature as well. When she feels a strong sense of injustice she can’t censor that. She's all or nothing in my opinion, which is really interesting to play.

Valerie’s struggling with her workload at the start of this series. She has a very large extended family and one particular aunt, who owns a ballet school, has moved to Frinton to retire. Her aunt leaves her in charge of the dance school in addition to her midwife duties. Valerie’s a much bigger woman than I am, because I would have just said no. So poor Valerie is teaching toddler tap and baby ballet as well as delivering babies. Thankfully help isn’t too far away.

Leonie: Lucille meets a young Jamaican mother called Alicia Palmer and they strike up a friendship. Alicia invites her to a weekly Sunday gathering. Her husband is a pastor and they gather, sing hymns and worship because, I suppose at the time, their experience of mainstream church was not the most pleasant. So once a week they gather in Alicia’s front room and her husband carries out the service. That was a really interesting and touching storyline.

I think for any immigrant to come here it’s hard because you want to fit in. Lucille is torn: she wants to fit in, but also wants to have reminders of home and some home comforts, which is what Alicia provides. At the beginning Lucille is quite conflicted because if she goes to Alicia’s is she then not trying to fit in? But she soon realises she might be able to have both, to have some home comforts now and again, and still fit into her new world.

Just being in London is an interesting journey for Lucille. I don’t think Lucille has ever experienced city life before; she’s had her rural upbringing and her training in Somerset. It’s been an eye opener for her, and she’s made some great friends like Valerie and Phyllis, and I suppose she’s been toughened up by some of the experiences she’s faced.